Cirsium helenioides
Cirsium tracyi
melancholy thistle
Tracy's thistle
single, erect, ± arachnoid-tomentose;
branches 0 or few, ascending.
1–several, erect or ascending, thinly gray-tomentose or ± glabrate;
branches few to many, ascending.
oblong to broadly lanceolate, 20–40 × 4–8 cm, finely spinulose-dentate or proximal cauline pinnatifid, lobes undivided, finely spinulose-dentate, main spines 1–2 mm, abaxial faces white-tomentose (with non-septate trichomes), adaxial glabrous;
basal present at flowering, petiolate, bases tapered;
cauline sessile, reduced distally, bases clasping, not decurrent;
distal (few, well separated), oblong or linear, the uppermost reduced to linear bracts.
blades elliptic to oblong, 8–40 × 1–12 cm, margins weakly to strongly undulate, spinose-dentate or shallowly to deeply lobed, lobes ascending to spreading, ± triangular, mostly well separated, spinulose and coarsely dentate or cleft into 2–3 lanceolate to triangular, often entire-margined, spine-tipped divisions, main spines 2.5–7+ mm, abaxial faces densely gray-tomentose, adaxial thinly tomentose;
basal sometimes present at flowering, winged-petiolate;
principal cauline becoming sessile and progressively reduced distally, widest at bases, bases ± auriculate-clasping to short-decurrent;
distal cauline reduced, often spinier.
2–10(–30) cm (elevated above distal leaves).
0–10+ cm.
broadly ovoid, 2–3 × 2–3.5 cm, glabrous or loosely arachnoid.
ovoid to hemispheric or broadly campanulate, 2–3 × 1.7–3.5 cm, loosely arachnoid on phyllary margins or glabrate.
red-purple, 25–30 mm, tubes 10–23 mm, throats 8–14 mm (noticeably wider than tubes), lobes 7–10 mm;
style tips 4–5 mm.
white to lavender or pink-purple, 23–30 mm, tubes 9–14 mm, throats 5.5–10.5 mm, lobes 5.5–9.5 mm;
style tips 4–7 mm.
in 8–10 series, imbricate, green, ovate or lanceolate (outer) to linear-lanceolate (inner), abaxial faces with a prominent elongate glutinous ridge, outer and middle tightly appressed, margins entire, apices with ascending, weak spines 0–1 mm;
apices of inner phyllaries attenuate, flat.
in 6–10 series, imbricate, ovate to lanceolate (outer) to linear-lanceolate (inner), margins entire, abaxial faces with prominent glutinous ridge;
outer and middle appressed, spines spreading, slender to stout, 2–6 mm;
apices of inner often flexuous, narrow, flat, ± entire, spineless or tipped with weak spines.
borne singly or less commonly 2–5 in terminal clusters.
1–many, terminal on branches and often in leaf axils, in leafy, ± corymbiform arrays.
light brown, 3–5 mm, bodies and apical collars concolorous;
pappi 20–30 mm.
light to dark brown, 6–7 mm, apical collars colored like body or rarely yellowish, narrow;
pappi 20–23 mm, usually noticeably shorter than corolla.
= 34.
= 24.
Cirsium helenioides
Cirsium tracyi
Cirsium helenioides is one of only two species of the genus that have native populations in the Old World and the flora area. Neither reaches the North American mainland.
The conservation status of Cirsium helenioides is not known; it is known in the flora area only from a single fjord and possibly should be considered of conservation concern.
of conservation concern
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Cirsium tracyi occurs from eastern Utah and western Colorado south in the Colorado Plateau and southern Rocky Mountains to northwestern New Mexico. Large-headed plants of Cirsium tracyi and small-headed individuals of C. undulatum are sometimes difficult to distinguish. P. L. Barlow-Irick (unpubl.) found that although there is much overlap in floral measurements of C. tracyi and C. undulatum, the means for some of these characters are statistically significant. Corolla lobes of C. tracyi, for instance, average about 7 mm and those of C. undulatum about 10 mm. The species differ in chromosome number as well.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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iNaturalist
USDA Plants Database
SW CO Wildflowers
